Pau270897

**Paulette**
 * __ Black Holes __**

A black hole is more than just a hole in space. It depends on the mass of the dying star to stimulate how big and massive a black hole would be. In general a black hole is super massive monster that swallows everything that it’s near it, even light. Scientists cannot detect black holes directly, they detect them indirectly by watching stars that are acting different that usual, or their orbits have an unusual shape. Sometimes the gas atoms heath the gas near the event horizon to several million degrees. This heat radiates from the gas as X-rays. Astronomers can detect this radiation with X-rays telescopes. Scientists have detected more than one black hole in the Milky Way, but no one has yet discovered a black hole for certain. **Characteristics of a black hole:** A black hole is made of singularity where all the super massive gravity is into a single point in the center of a black hole, the mass of singularity is not infinite but the density is because the point has no size. The event horizon it’s the point of no return, if an object passes thru the event horizon it is destroyed. Schwarzschild radius is the distance of space-time between the event horizon and singularity; this distance determines the size of a black hole. To form a black hole a star has to be massive like our sun. Before it transform into a black hole it has to go though some phases. First it is just a stellar nebula, then it get enough mass and heat to form a star, then it becomes a massive star. Billions of years after it expands and it transforms into a red giant. Then it causes an explosion, which causes a supernova. After the supernova there's no barrier left no force sufficient to hold the black gravity in space and then matter will contract into a single point named singularity that’s the center of a black hole. Singularity will then break the red of time-space creating a black hole. There are two types of black holes. One of them is a stellar black hole that is created if a dying star is super massive. A stellar black hole has the same process that forms a stellar nebula: accretion. As the star collapses matter accretes into where the core once was making the stellar black hole with every passing second. Scientists haven’t found something denser than the point at the bottom of the black hole. The more massive the stellar black hole grows, the more mass it swallows. Another type of black hole is, the supermassive black hole. These kinds of black holes are the most massive body in the whole universe. A supermassive black hole has more than 10 billion solar masses together. There are two theories about the formation of a supermassive black hole. The first one says that a stellar black hole keeps taking in matter, as it takes matter it gains mass. Eventually it transforms into a supermassive black hole. The other theory is that two black holes collide and they join together to form huge, supermassive black hole. Theoretically, each time two black holes fuse, they give away more energy than all the stars in the universe combined. Scientists have found that supermassive black holes seem to be at the heart of some galaxies. That means that our galaxy may have a supermassive black hole in the middle and we are going around it. Some scientists have theorized that mini black holes can exist. A black hole the size of a house would have as much mass as a mountain and its singularity would be the size of an atom. A black hole is not a solid object, but it is sharpen like a sphere. If the singularity theory is true it means that inside a black hole there is not really a hole, or tunnel to go anywhere else in the universe. But unfortunately we can’t say if it’s true or not because nothing can escape from a black hole. **The search for the invisible:** One way to find a black hole is to look for evidence of its effect on the other bodies in space around it. Scientists look for areas in the universe where time, light, and matter are oddly affected. According to Einstein’s theory, mass can bend energy. The light waves are energy. Mass and gravity detract light waves and bend them, altering their course, this is known as the gravitational lens effect. This effect causes an Einstein ring. An Einstein ring looks like a circle of light around a patch of darkness. As space-time is pulled into a black hole, light is twisted around it. The first approach astronomers took was to look for black holes in binary star systems. Binary star systems are two stars close together that orbit around each other. Another way to find a black hole is to look into a gas nebula. Astronomers realized that the gas and dust of a nebula could fall into a black hole, and if it did, then it would make the speed to increase to a speed that it would be heated to extremely high temperatures, giving out light, and other types of electromagnetic radiation, like radio waves. Scientists looked for evidence. Unfortunately this search wasn’t successful. It may have been that there were black holes where they were looking, but that the amount of gas and dust going into them was so small that the radio waves were too weak to detect. **Myths and Facts:** The matter outside a black hole helped the astronomers to estimate how dense the center of a black hole is, the estimation is that the center of a black hole is ten times as dense as matter inside a neutron star. The center of a black hole seems to approach infinity. Some theorize that for every black hole, a white hole exists. White holes are the opposite of a black hole, if a black hole draws in any matter that crosses its event horizon, a white hole spits out matter from its event horizon. White holes are only theoretical. Another well-known idea involves a wormhole. A wormhole is a tunnel between a white hole and a black hole. If anything can survive from being crushed in a wormhole would most likely die from intense radiation. If a traveler could survive, the time travel would take place when the traveler entered a black hole. If someone would travel through the wormhole, and exit out the other side. The person would be hyperspace, an entirely different space and time. In conclusion black holes are more than just a hole in space and now you know why. In the future we hope that scientists find more specific information about black holes by sending a machine to study a Black hole from the outer space. **References:** Parker, Katie, __Black holes__, United States of America, Marshall Cavendish Benchmark Oxlade, Chris, __The mystery of BLACK HOLES__, Chicago, Illinois, 2000, 2006 Zimmerman, Barry E., David J., __Why nothing can travel faster than light…__ “Black holes”, [], [], (7 Dec. 2010) Amigos School Computer Laboratory "Black hole." [] 2004. [] Amigos school computer laboratory.